1. Field of the Invention
The present invention relates generally to roll forming machines having rolls for working sheet metals, and more particularly to that type of roll forming machines which serve to form opposite edges of sheet metals into bent sectional shapes.
2. Description of the Prior Art
A typical roll forming machine for processing sheet metals into bent sectional shapes is provided with a plurality of horizontally mounted pairs of vertically aligned upper and lower rolls, and the sheet metals to be worked are fed between the upper and lower rolls of each pair with rotation thereof. Of course, the upper and lower rolls of each pair are designed to serve as dies to produce bends in the sheet metals in cooperation with each other. Also, the pairs of the upper and lower rolls are so designed that the sheet metals are slightly worked by the initial pair of upper and lower rolls and additionally bent stage by stage by the succeeding rolls and finally formed to desired sectional shapes by the last pair of rolls.
In conventional forming machines, the shafts of the upper and lower rolls have been disposed in parallel with each other, and such construction is very complicated.
Accordingly, in the conventional roll forming machines, it has been very difficult and time-consuming to adjust the clearance between the upper and lower rolls depending upon the thicknesses of sheet metals to be worked.
Also, another disadvantage with the conventional forming machines has been the fact that the bends to be made on the sheet metals will be hindered by the upper roll and their shafts which are disposed in parallel with the axes of the lower rolls.
Still another disadvantage with the prior art forming machines has been that the rolls can be only used to form sheet metals to a given sectional shape and accordingly it has been necessary to change the rolls when it is desired to form different sectional shapes on sheet metals.
Also, the conventional roll forming machines have been costly because of complicated construction.